1. Field of the Invention
The present invention relates to a distributed channel hopping method in a lower power wireless ad-hoc network, and more particularly, to a method of efficiently and stably transmitting and receiving beacons of router nodes in a wireless ad-hoc network between router nodes and neighboring nodes.
2. Description of the Related Art
The IEEE 802.15.4 medium access control (MAC) is a conventional data link layer technology used to constitute a low power wireless network. Under the IEEE 802.15.4 MAC, all nodes included in the low power wireless network share a single channel and use a random medium access method to perform communication. If the number of nodes increases, packets collide due to frequent message exchange for channel access. Furthermore, when IEEE 802.15.4 MAC used in the environment where the heterogeneous wireless devices (e.g. a wireless local area network (LAN), Bluetooth, etc.) are exist, the communication quality deteriorates due to interferences from the heterogeneous wireless devices which uses the same radio frequency band.
In an IEEE 802.15.4 MAC multi-hop network, personal area network (PAN) coordinators and coordinator nodes need to periodically transmit beacons thereof. To this end, it is necessary to form multiple superframe duration (SD) slots in a single beacon interval and schedule multiple SD slots of each coordinator so as not to overlap. The forming of multiple SD slots needs a very small ratio of multiple SD slots with respect to the beacon interval. Thus, communication efficiency dramatically deteriorates in a multiple-hop topology.